Semiconductor components, such as wafers, singulated dice, and chip scale packages must be tested and burned-in prior to use in multi chip modules and other electronic devices. For performing these test procedures, temporary electrical connections can be made to contacts on the components. Test signals can then be transmitted through the temporary electrical connections to the integrated circuits contained on the components. For wafers and singulated dice, the contacts typically comprise aluminum bond pads, or alternately solder bumps. For chip scale packages the contacts typically comprise solder bumps.
The temporary electrical connections can be made to the contacts on the components using an interconnect. The interconnect includes contact members configured to electrically engage the contacts on the components. U.S. Pat. No. 5,483,741 to Akram et al. describes an exemplary interconnect for singulated dice. The '741 interconnect includes a silicon substrate with raised contact members covered with a metal silicide layer.
One aspect of these interconnects is that the contact members must be capable of forming low resistance, or "ohmic", electrical connections with the contacts on the components. Typically, the contacts on the components include a native oxide layer (e.g., aluminum oxide) that must be penetrated to electrically contact the underlying metal.
However, the contact members on the interconnect can also include native oxide layers that can affect the electrical characteristics of the temporary electrical connections with the components being tested. For example, metal silicide contact members are subject to oxidation, which increases the electrical resistivity of the temporary electrical connections with the components. The electrical resistivity of the temporary electrical connections is also a function of the resistivity of the materials which form the contact members. It would be desirable to be able to form the contact members on interconnects with non-oxidizing, low-resistivity materials.
Another aspect of interconnects used for testing semiconductor components is that electrical paths must be made between the contact members on the interconnects, and external test circuitry. These electrical paths sometimes include wire bonds. If the contact members are formed of a material, such as a metal silicide, that cannot be easily wire bonded, then additional layers must be added to the interconnect to provide wire bonding sites. It would be desirable to be able to form the contact members on interconnects with wire-bondable materials.
In view of the foregoing, the present invention is directed to an improved interconnect having contact members covered with a non-oxidizing, wire bondable layer.